We mortify sin by cherishing the principle of holiness and sanctification in our souls, labouring to increase and strengthen it by growing in grace, and by a constancy and frequency in acting of it in all duties, on all occasions, abounding in the fruits of it. Growing, thriving, and improving in universal holiness, is the great way of the mortification of sin. The more vigorous the principle of holiness is in us, the more weak, infirm, and dying will be that of sin. The more frequent and lively are the actings of grace, the feebler and seldomer will be the actings of sin. The more we abound in the ‘fruits of the Spirit,’ the less shall we be concerned in the ‘works of the flesh.’ And we do but deceive ourselves if we think sin will be mortified on any other terms.

—John Owen
Works of John Owen, 3:552.